When rearing children, parents should teach their children to always do their best. This is a great principle which will greatly benefit the child. As the child grows, this principle will teach the child to do his best in school, in extra-curriculum activity, in marriage, in friendships, in employment, etc. There is nothing wrong with encourage children to strive to do their best at whatever they do.

Some are arrogant, as though I were not coming to you. But I will come to you soon, if the Lord wills, and I will find out not the talk of these arrogant people but their power. (1 Corinthians 4:18-19, ESV)

In writing his letter to the church in Corinth, the apostle Paul anticipated resistance from some of the members of the Corinthian congregation.